BenaFog Share definition Flag The mental state 12 hours after taking Benadryl. No other symptoms besides the lump, and a benadryl seems to be taking it down. Now I get to spend the next 18 hours in a BenaFog. BenaFog by james77 April 29, 2009 0 0 Get merch Get the BenaFog mug. Buy Now — $32.95 See more merch